Calling a 5% change in the Shanghai Composite index a "hard hit" is an overstatement, given what has been happening there over the last months (particularly April-September).
Well it is the biggest drop single day drop since the larger losses in June/July so I think that it is justified in calling it a hard hit.
Well, the American holiday might have something to do with the lack of response in U.S. markets. I suspect that this also indicates a lack of "reality" in the Chinese stock markets. The Chinese economy is fairly strongly integrated with the rest of the world, but the Chinese markets don't reflect the economy as well as they could. Which is to say, the economic decline has been visible for a while and only now are the Chinese markets catching up.